1. Technical Field
The present application relates to a vacuum drum for the use in container treatment machines, in one possible embodiment labeling machines, with a drum element that is journaled for rotation in a carrier arrangement and that is configured to be powered for rotation about a drum axis. The vacuum drum also comprises at least one vacuum channel that is configured in the drum element and opens into a vacuum opening, as well as comprises a rotary distributor or vacuum distributor for connecting the at least one vacuum canal configured in the drum element with a vacuum source. The rotary distributor or vacuum distributor comprises at least one first sealing surface at a first distributor element that does not rotate with the drum element, as well as at least one second sealing surface provided at the drum element for a sealing position against the first sealing surface.
2. Background Information
Background information is for informational purposes only and does not necessarily admit that subsequently mentioned information and publications are prior art.
Vacuum drums for use in container treatment machines, in one possible embodiment labeling machines, are known and serve, for example, as transport drums for the advancing, or forwarding of labels and/or, respectively, are a component, as cutting drums, of a cutting arrangement of an labels aggregate for processing of endless labels or label material. During operation the respective vacuum drum is constantly or substantially constantly or intermittently operated under vacuum, by way of a rotary distributor, or vacuum distributor. Furthermore, the rotary distributor and vacuum distributor comprises at least two sealing surfaces, namely a first sealing surface which is arranged at a distributor element that does not rotate with the vacuum drum, or, respectively, does not rotate with the drum element; and the rotary distributor and vacuum distributor comprises a second sealing surface which rotates with the drum element, or, respectively, is provided at the drum element. Both sealing surfaces lie mutually close together, for example, due to the force that is generated by a spring arrangement. In the case of known vacuum drums the sealing surface intended at the drum element is formed by a surface of the drum element that is basically made of metal, while the distributor element that does not rotate with the drum element of the rotary distributor, or vacuum distributor just as the sealing surface provided at this distributor element, is made of plastic, or synthetic material so as to reduce friction losses by using this composite material comprising metal and plastic, or synthetic material.
However, this arrangement has the disadvantage that friction losses cannot substantially be avoided, restricted, and/or minimized and the resulting frictional heat flows directly into the drum element made of the metallic material, so that the drum element is heated during the operation to a considerable extent, while there does not arise, through the plastic, or synthetic material of the drum element of the rotary distributor, or vacuum distributor, that does not rotate with the drum element, an appreciable heat reduction, inasmuch as in comparison to the metallic material, the plastic, or synthetic material does not reduce the frictional heat, or in a very low amount. For this reason it is often usual and necessary or desired to cool the drum element with a chilling medium, e.g., with water, oil, or an air pressure which causes an additional constructive expenditure.
The warming, or heating, or, possibly, overheating of the drum element leads to the fact that there arise operational changes, for example, changes of the diameter of this drum element which changes impair the operation of the vacuum drum. In one possible embodiment, when the vacuum drum is configured to operate as a cutting drum of a cutting arrangement, the frictional heat that is introduced into the drum element leads to changes of the cutting gap which has negative consequences with respect to the quality of the cut and/or the processing speed.
To avoid, restrict, and/or minimize these disadvantages, embodiments have become known in which the drum element is actively subjected to heat, so as to maintain the drum element independent of working conditions constantly or substantially constantly or intermittently at a certain temperature, from which results that the dimensional relations in the cutting gap are not varied and the quality of the cut is influenced merely by the operational settings. Disadvantageously in such devices are the substantially constructive and apparatus-related expenditures and the high energy costs caused by the heating.